Zimmers.NET Files (formerly ftp.funet.fi)

/pub/cbm/firmware/drives/new/1541/


This directory contains ROMs of 1540, 1541, 1541C and 1541-II drives.
The ROM checksums are valid. If you add the byte values together (adc data:adc #0), the sum of the $c000-$dfff ROM will be $c0, and the $e000-$ffff ROM will add up to $e0. This applies also to the halves of the 1541-II ROM. The 2764 and 27128 eproms can be used as replacements.

Subdirectories

hacks/
3rd party modifications to the firmware
schematics@
Schematic diagrams

Files

1540-c000.325302-01.bin 2009-08-18 8192
The ROM chip for $c000-$dfff. This seems to be the same on all
models before the 1541-II.

1540-e000.325303-01.bin 2009-08-18 8192
The firmware of an 1540 (the drive that the C64 wouldn't keep up with).
The revision number might be something else than -01. A speciality of
this chip is the power-up message: 73,CBM DOS V2.6 V170,00,00. Did
Commodore want to call the drive V170 first? The ROM checksum is correct.
The long-board 1541 had the same hardware as the 1540; this upper ROM
was the only difference. The lower ROM was 325302-01 on both drives.

1541-c000.325302-01.bin 2009-08-18 8192
The ROM chip for $c000-$dfff. This seems to be the same on all
models before the 1541-II.

1541-dos_diffs.zip 2013-05-15 7216
Assembly differences between various 1541 roms

1541-e000.901229-01.bin 2009-08-18 8192
This is believed to be the first revision of the 1541 firmware. The
service manual says that this ROM is for North America and Japan only.
According to it, a 901229-02 also exists, but not in North America.
901229-03 is said to be the first version that is usable in Europe.

1541-e000.901229-02.bin 2009-08-18 8192
Second version of the 1541 firmware. Uploaded by Raymond Day
<raymondday@hotmail.com>. Two delay loops are shorter than in 901229-03,
and the checksum byte at $fee6 has been adjusted accordingly.

1541-e000.901229-03.bin 2009-08-18 8192
The firmware of an old-style 1541 with long board.
This ROM has an autobooting feature: if CLK and DATA are held low
during bootup, the drive will wait for them to raise, and execute
a "&*" command.

1541-e000.901229-04.bin 2020-08-04 8192
Take from an SX-64

1541-e000.901229-05.bin 2009-08-18 8192
The firmware of an old-style 1541 with short board.

1541-e000.901229-06AA.bin 2009-08-18 8192
The firmware of an old-style 1541 with short board.

1541-II.251968-03.bin 2009-08-18 16384
1541-II firmware. Released in 1987.

1541-II.355640-01.bin 2009-08-18 16384
1541-II firmware. This version only appears in drives with the newtronics

mechanisms with belt type drives and no track 0 sensor.

1541C-to-1541-II.txt 2009-08-18 11214
A comparison of the 1541C and 1541-II firmware by Wolfgang Moser.
The support for the optical "track 0" sensor, which was introduced
in the 1541C firmware, was removed in the 1541-II firmware.

1541C.251968-01.bin 2009-08-18 16384
The firmware of an old-style 1541 in white case. This drive was introduced
around the same time with the C128 and the 1570, to make it look like the
C128 and the 1570, which was also in a white 1541-style case. The C128 was
also white. This drive has an optical track 1 sensor, but it won't be used
unless the jumper J3 on the board is cut.

The $c000-$dfff part of this chip is identical to the 325302-01 ROM.

1541C.251968-02.bin 2009-08-18 16384
An upgrade ROM for the 1541C. There are patches in both 8k halves.
1541C.251968-02.txt 2009-08-18 1847
Release notes for the 251968-02.

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